The popular online payment company's plans for an initial public offering to raise as much as US$80.5 million were temporarily derailed when PayPal was sued for patent infringement by CertCo. In its complaint filed with the U.S. District Court for the District of Delaware, CertCo alleges that PayPal's service infringes CertCo's U.S. Patent No. 6,029,150, entitled "Payment and Transactions in Electronic Commerce System."

Not surprisingly, PayPal has said that CertCo's lawsuit is "without merit." But a judge or jury--not PayPal--ultimately will decide that issue (unless the parties settle). In an amended filing with the Securities and Exchange Commission in response to the lawsuit, PayPal acknowledged that it does not know how the judicial system will treat it.